Shipments of cement in powder form are typically transported in water-tight hopper style trucks that are unloaded at a receiving cement silo with the aid of conventional truck feeders and air supply systems. The unloading process takes about forty-five minutes to an hour for each truck. During this lengthy unloading process, the truck engine is running at a high rpm to maintain a constant flow of cement from the truck to the silo. Workers at the site are thus subjected to continuous, detrimentally high noise levels, particularly when a number of trucks are unloading simultaneously.
Furthermore, this lengthy unloading process increases fuel consumption and capital equipment, maintenance and labor costs. The truck driver is idle and may do nothing but wait during the unloading process. As the equipment is specialized, it may limit the opportunity for back hauls. Additionally, hopper style trailers are more expensive than conventional dump trailers, and have high capacity feeder and air systems on board which must be maintained to accommodate the transfer of the load from the truck to the receiving silo.